Gusset Bag, Spout-Attached Gusset Bag, And Method Of Manufacturing The Same

ABSTRACT

The gusset bag includes an opposing pair of flat surface sections and an opposing pair of side surface sections folded inward. Moreover, the pair of flat surface sections and the pair of side surface sections includes a first film material that forms a first flat surface section and at least a first side surface section, and a second film material that forms the other section thereof Furthermore, a side edge seal section is formed in which a side edge section of the first film material and a side edge section of the second film material are sealed.

TECHNICAL FIELD

The present invention relates to a gusset bag, a spout-attached gussetbag, and a method of manufacturing the same.

Priority is claimed on Japanese Patent Application No. 2011-188309,filed Aug. 31, 2011, the content of which is incorporated herein byreference.

BACKGROUND ART

For a packaging bag for liquid or semi-liquid contents such as jellybeverages, standing pouches or flat bottom type gusset bags are used.Especially for the purpose of storing jelly beverages, a gusset bag iswidely used, whose contents can be easily pushed out by being squeezedby hand.

For example, as shown in FIGS. 12 and 13, a spout-attached gusset bag101 is known that comprises a gusset bag 110 which stores the contents,and a spout 120 which is attached to the gusset bag 110 and dispensesthe contents from the gusset bag 110 (for example, refer to PatentDocument 1). The gusset bag 110 is provided with an opposing pair offlat surface sections 111, and a pair of side surface sections 112 whichconnect the side edges of the two flat surface sections 111 and arefolded inward opposite to each other.

In the spout-attached gusset bag 101, four side edge seal sections 113are formed by the side edge sections of the flat surface sections 111and the side edge sections of the side surface sections 112 being heatsealed.

DOCUMENT OF RELATED ART Patent Document

[Patent Document 1] Japanese Unexamined Patent Application, FirstPublication No. 2004-196414

SUMMARY OF INVENTION Technical Problem

However, there is a case in which a user feels pain when he or shesqueezes the spout-attached gusset bag 101 strongly by hand, and a sideedge seal section 113 touches the hand. That is, the side edge sealsection 113 is formed such that it projects toward the outside of thegusset bag 110, the stiffness of the side edge seal section 113 is high,and the end 113 a is relatively sharp. Therefore, there is a case inwhich, when a user squeezes it by hand, he or she feels pain by the end113 a cutting into the hand. In particular, in the case where thecontents are a jelly beverage or the like, normally a user ingests thecontents by pushing them out by squeezing the gusset bag 110 by hand.Therefore, it is desirable to reduce the pain felt when squeezing thegusset bag 110 by hand.

It is an object of the present invention to provide a gusset bag thatcan reduce the pain that a user feels when he or she squeezes it byhand, and a spout-attached gusset bag in which a spout is attached tothe gusset bag.

Furthermore, it is another object of the present invention to provide amethod of manufacturing a gusset bag that can reduce the pain that auser feels when he or she squeezes it by hand, and a method ofmanufacturing a spout-attached gusset bag in which a spout is attachedto the gusset bag.

Solution to Problem

According to a first aspect of the present invention, a gusset bagincludes an opposing pair of flat surface sections and an opposing pairof side surface sections folded inward.

Moreover, the pair of flat surface sections and the pair of side surfacesections includes a first film material that forms a first flat surfacesection and at least a first side surface section, and a second filmmaterial that forms the other section thereof. Furthermore, a side edgeseal section is formed in which a side edge section of the first filmmaterial and a side edge section of the second film material are sealed.

According to a second aspect of the present invention, in the firstaspect, the first film material forms the first flat surface section andthe pair of side surface sections, and the second film material forms asecond flat surface section.

According to a third aspect of the present invention, a spout-attachedgusset bag includes a spout attached to the gusset bag of the first orthe second aspect.

According to a fourth aspect of the present invention, a method ofmanufacturing a gusset bag is a method of continuously manufacturing thegusset bag of the second aspect, and includes the following steps (α1)and (α2).

(α1) a step of conveying a long first film material used to form a firstflat surface section and a pair of side surface sections, together witha long second film material used to form a second flat surface section,in a state in which the first film material is folded such that aplurality of first flat surface sections and a plurality of pairs ofside surface sections are formed in parallel in a longitudinal directionthereof, and

welding a part between adjacent side surface sections of the first filmmaterial to the second film material in the longitudinal direction andcutting them, welding each part from side surface sections positionednear both side edges of the first film material to the side edges, tothe second film material in the longitudinal direction and cutting them,and obtaining a plurality of cylindrical film materials, eachcylindrical film material including flat surface sections and sidesurface sections with two side edge seal sections formed.

(α2) a step of welding and cutting the cylindrical film material in awidth direction thereof, and separating the cylindrical film materialinto a plurality in the longitudinal direction.

According to a fifth aspect of the present invention, a method ofmanufacturing a spout-attached gusset bag uses the method ofmanufacturing a gusset bag of the fourth aspect, and includes attachinga spout to each top part of cylindrical film materials separated in thelongitudinal direction when sealing the top part.

Effects of Invention

According to the gusset bag and the spout-attached gusset bag of thepresent invention, it is possible to reduce the pain that a user feelswhen he or she squeezes it by hand.

Furthermore, according to the method of manufacturing a gusset bag ofthe present invention, it is possible to obtain a gusset bag that canreduce the pain that a user feels when he or she squeezes it by hand.

Moreover, according to the method of manufacturing a spout-attachedgusset bag of the present invention, it is possible to obtain aspout-attached gusset bag in which a spout is attached to a gusset bagthat can reduce the pain that a user feels when he or she squeezes it byhand.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing a spout-attached gusset bag of anembodiment of the present invention.

FIG. 2 is a rear view of the spout-attached gusset bag of FIG. 1.

FIG. 3 is a cross-sectional view through straight line I-I′ of thespout-attached gusset bag of FIG. 1.

FIG. 4 is a perspective view showing how contents are stored in thespout-attached gusset bag of FIG. 1.

FIG. 5 is an enlarged front view of the vicinity of an upper sealsection of the spout-attached gusset bag of FIG. 1.

FIG. 6 is a cross-sectional view through straight line II-II′ of thespout-attached gusset bag of FIG. 5.

FIG. 7 is a perspective view showing a manufacturing process of aspout-attached gusset bag of an embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a manufacturing process of aspout-attached gusset bag of an embodiment of the present embodiment.

FIG. 9 is a perspective view showing a manufacturing process of aspout-attached gusset bag of an embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a manufacturing process of aspout-attached gusset bag of an embodiment of the present embodiment.

FIG. 11 is a cross-sectional view showing a modified example of a gussetbag of an embodiment of the present invention.

FIG. 12 is a front view showing a conventional spout-attached gussetbag.

FIG. 13 is a cross-sectional view through straight line of thespout-attached gusset bag of FIG. 12.

DESCRIPTION OF EMBODIMENTS

A gusset bag and a spout-attached gusset bag of the present inventionhave similar configurations except for the existence of a spout. Thatis, the gusset bag of the present invention has the same configurationsas the spout-attached gusset bag except that it does not have a spout.Hereunder, an embodiment of a gusset bag and a spout-attached gusset bagof the present invention will be described in detail showing an exampleof a spout-attached gusset bag including a spout.

As shown in FIG. 1, a spout-attached gusset bag 1 of this embodimentincludes a gusset bag 10, and a spout 20 attached in a fluid-tightmanner to the top of the gusset bag 10. That is, the spout 20 isattached to one end side in the vertical direction (for example, theup-and-down direction in FIG. 1) of the gusset bag 10. In the followingdescription, the edges of the gusset bag 10, and the edges of a flatsurface section and a side surface section (described later) in thedirection perpendicular to the vertical direction (for example,horizontal direction in FIG. 1) may be referred to as “side edges”.

The gusset bag 10, as shown in FIGS. 1 to 3, includes an opposing pairof flat surface sections 11 and 12, and an opposing pair of side surfacesections 13 and 14, wherein each of the side surface sections 13 and 14connects the facing side edges of the flat surface sections 11 and 12.The flat surface section 11 (first flat surface section) and the pair ofside surface sections 13 and 14 are formed from a sheet of filmmaterial. That is, this gusset bag 10 is composed of two sheets of filmmaterial which are a first film material that forms the flat surfacesection 11 and the pair of side surface sections 13 and 14, and a secondfilm material that forms the flat surface section 12 (second flatsurface section).

The side surface sections 13 and 14 are folded toward the inside of thegusset bag 10 such that respective folding lines 13 a and 14 acorrespond to each other.

As shown in FIGS. 2 and 3, in the gusset bag 10, two side edge sealsections 15 are formed, in which both side edge sections of the flatsurface section 12 formed of the second film material, and the side edgesections of the side surface sections 13 and 14 formed of the first filmmaterial, are heat sealed (thermally welded). Furthermore, as shown inFIGS. 1 and 2, on the top of the gusset bag 10, an upper seal section 16is formed in which the flat surface sections 11 and 12 and the sidesurface sections 13 and 14 are sealed. Moreover, on the bottom of thegusset bag 10, a lower seal section 17 is formed in which the opposinginner surfaces of the flat surface sections 11 and 12 and the sidesurface sections 13 and 14 are heat sealed. In this manner, the gussetbag 10 is formed.

Accordingly, as shown in FIG. 4, the spout-attached gusset bag 1 canstore contents in the gusset bag 10.

In the upper seal section 16, the opposing inner surfaces of the flatsurface sections 11 and 12 and the side surface sections 13 and 14 areheat sealed. Furthermore, in the upper seal section 16, it is preferablethat the contact surfaces of the side surface section 13 be sealed andthe contact surfaces of the side surface section 14 be sealed. Thesealing of the contact surfaces of the side surface section 13 and thecontact surfaces of the side surface section 14 in the upper sealsection 16 may be performed for example while forming seal sections 18as shown in FIGS. 5 and 6. In the seal sections 18, two punch holes areformed in opposing locations in the vicinities of the side edges of eachof the side surface sections 13 and 14, and the inner surfaces 11 a and12 a of the flat surface sections 11 and 12 are heat sealed in the punchholes. Moreover, the contact surfaces of the side surface section 13 andthe contact surfaces of the side surface section 14 in the upper sealsection 16 may be directly glued by an adhesive, a heat seal using afilm having heat sealing characteristics, or a double-sided adhesivetape.

In the gusset bag 10 of the spout-attached gusset bag 1, since the sideedge sections of the first film material and the side edge sections ofthe second film material are sealed, two side edge seal sections areformed. As a result, compared with a conventional gusset bag having fourside edge seal sections formed, the number of side edge seal sectionsthat touch the hand is less, so that the pain that a user feels when heor she squeezes it by hand can be reduced.

Furthermore, in the spout-attached gusset bag 1, the flat surfacesection 11 and the side surface sections 13 and 14 of the gusset bag 10are formed of a sheet of film material. Accordingly, as shown in FIG. 4,no side edge seal section is formed near the flat surface section 11 ofthe gusset bag 10, and there is no protruding section. By so doing, inthe case where the gusset bag 10 is gripped by hand from the side nearthe flat surface section 11, since the part of the gusset bag 10 thattouches the palm is smooth, the pain that a user feels can be furtherreduced.

It is preferable that the width d₁ (refer to FIG. 3) of the flat surfacesection 12 formed of the second film material be within ±5 mm of thewidth d₂ (refer to FIG. 3) of the flat surface section 11 formed of thefirst film material. By so doing, it is possible to more easilymanufacture the gusset bag 10 that enables a reduction in the pain thata user feels when he or she holds it.

The opposing pair of flat surface sections 11 and 12 form the frontsurface and the rear surface of the spout-attached gusset bag 1,respectively. In the present invention, the flat surface section 11 maybe used as the front surface and the flat surface section 12 may be usedas the rear surface, or the flat surface section 12 may be used as thefront surface and the flat surface section 11 may be used as the rearsurface.

Examples of a first film material that forms the flat surface section 11and the side surface sections 13 and 14 include a single layer film or alaminated film having a multilayer structure. The first film material ispreferably a laminated film from the point that it can provide a varietyof functions, and is more preferably a laminated film that has aninnermost layer that can be heat sealed, a functional layer, and anoutermost layer.

Examples of a film used as the innermost layer include a non-orientedfilm formed of one or more selected from a group consisting ofpolyolefin resins such as low-density polyethylene (LDPE),medium-density polyethylene, high-density polyethylene, polypropylene(PP), and linear low-density polyethylene (LLDPE), mixed resins thereof,an ionomer resin, an ethylene-vinyl acetate copolymer, anethylene-acrylic acid copolymer, an ethylene-acrylic acid methylcopolymer, and an ethylene-methacrylic acid copolymer.

The thickness of the innermost layer is preferably 30 to 200 μm.

For a film used as the outermost layer, a film having high mechanicalsuitability and printability is preferable. Examples thereof includefilms formed of synthetic resins such as polyethylene terephthalate,polyamide, polypropylene, polycarbonate, and polyacetal. These films maybe non-oriented films, or oriented films stretched uniaxially orbiaxially. For a film used as the outermost layer, in terms ofprintability, a uniaxially or biaxially oriented film is preferablyemployed.

Specific examples thereof include oriented plastic films such asbiaxially oriented polyethylene terephthalate (PET), biaxially orientedpolyamide (ONY), and biaxially oriented polypropylene (OPP).

In addition, if necessary, synthetic paper, cellophane, paper, nonwovencloth or the like can also be used.

The thickness of the outermost layer is preferably 12 to 25 μm.

The functional layer can be appropriately selected in accordance withrequired functions such as gas barrier properties, mechanical toughness,flex resistance, pierce resistance, shock resistance, wear resistance,cold resistance, heat resistance, and chemical resistance.

Examples of a film used for the functional layer include metal foilssuch as aluminum, iron, copper, and tin, films such as polyethyleneterephthalate, polyamide, polyvinyl chloride, polycarbonate, polyvinylalcohol, and ethylene-vinyl acetate copolymer saponification product,films obtained by applying polyvinylidene chloride to the above films orby vapor-depositing an inorganic material such as aluminum, siliconoxide, aluminum oxide, indium oxide, tin oxide, zirconium oxide, andmagnesium oxide on the above films, films of polyvinylidene chloride,and nonwoven cloth or a foamed film having heat insulating properties.

The functional layer may be a single layer or two or more layers.

It is sufficient if the thickness of the functional layer is a thicknessthat can satisfy the functions required for the gusset bag 10, and thethickness is preferably 6 to 20 μm.

Moreover, in the first film material, instead of providing a functionallayer, a vapor-deposited film having a vapor-deposited layer providedthereon may be employed for a film used as an outermost film.

Examples of a vapor-deposited layer include inorganic materials such asaluminum, silicon oxide, aluminum oxide, indium oxide, tin oxide,zirconium oxide, magnesium oxide.

Specific examples of the first film material include, for example, afilm formed of PET (12 μm)/Al (7 μm)/ONY (15 μm)/LLDPE (60 μm) in orderfrom the outermost layer.

For the second film material that forms the flat surface section 12, thesame film as the first film material that forms the flat surface section11 and the side surface sections 13 and 14 can be employed. It ispreferable that at least the innermost layer of the second film materialbe the same as the innermost layer of the first film material in termsof sealability.

As shown in FIGS. 1 and 2, the spout 20 includes an extraction tube 21which is inserted into the gusset bag 10 so as to extract the contents,and a cap 22 which is screwed to the top part of the extraction tube 21so as to close the extraction port (opening) of the extraction tube 21.The spout 20 is liquid-tightly attached to the upper seal section 16 byheat-sealing in a state in which the extraction tube 21 is sandwichedbetween the upper edge portions of the flat surface sections 11 and 12.

As a material of the spout 20, the material of at least a part of theextraction tube 21 which is sealed with the inner surface of the flatsurface section 11 is a synthetic resin.

Examples of a synthetic resin which forms at least the sealing portionof the extraction tube 21 of the spout 20 include a polyolefin resin, apolyamide resin, a polyester resin, a (meth)acrylic resin, a vinylchloride resin, a vinylidene chloride resin, polyether sulfone, anethylene-vinyl alcohol copolymer and the like. Among them, a polyolefinresin is preferably used in terms of excellent workability and low cost.

Examples of a polyolefin resin include a polyethylene-based resin suchas high-density polyethylene, medium-density polyethylene,high-pressure-process low-density polyethylene, linear low-densitypolyethylene, and an ethylene-vinyl acetate copolymer, an olefin-basedelastomer such as an ethylene-a-olefin copolymer, a polypropylene-basedresin such as polypropylene, an ethylene-propylene random copolymer, andan a-olefin-propylene random copolymer, a cyclic polyolefin resin andthe like. These resins may be blended to improve the performance, or maybe partially cross-linked for the purpose of improvement in heatresistance and the like.

The spout 20 may be formed of a single material, or may be formed tohave a multilayer structure formed of various resin layers.

In terms of sealability, the resin which forms at least the sealingportion of the extraction tube 21 of the spout 20 is preferably the sameas the resin which forms the innermost layer of the flat surfacesections 11 and 12.

(Manufacturing Method)

As a method of manufacturing a gusset bag of the present invention, amethod including the following step (α1) and step (α2) can be given.This manufacturing method is suitable for a case where the first filmmaterial forms one flat surface section (first flat surface section) anda pair of side surface sections, and the second film material forms thefilm material (the other flat surface section, second flat surfacesection) of the other section in the gusset bag.

(α1) a step of conveying a long first film material used to form a firstflat surface section and a pair of side surface sections together with along second film material used to form a second flat surface section, ina state in which the first film material is folded such that a pluralityof first flat surface sections and a plurality of pairs of side surfacesections are formed in parallel in a longitudinal direction thereof, and

welding a part between adjacent side surface sections of the first filmmaterial to the second film material in the longitudinal direction andcutting them, and welding each part from side surface sectionspositioned near both side edges of the first film material to the sideedges, to the second film material in the longitudinal direction andcutting them, and obtaining a plurality of cylindrical film materials,each cylindrical material including flat surface sections and sidesurface sections with two side edge seal sections formed.

(α2) a step of welding and cutting the cylindrical film material in awidth direction thereof (a direction perpendicular to the longitudinaldirection and parallel to the flat surface section), and separating thecylindrical film material into a plurality in the longitudinaldirection.

In the case of manufacturing a spout-attached gusset bag, in the step(α2), a spout is attached to each top part of cylindrical film materialsseparated in the longitudinal direction when sealing the top part.

Hereunder, an example of a spout-attached gusset bag 1 including agusset bag 10 is described in detail.

Step (α1):

As shown in FIG. 7, a long first film material 10A used to form a flatsurface section 11 and a pair of side surface sections 13 and 14 isconveyed using rollers or the like together with a long second filmmaterial 10B used to form a flat surface section 12, in a state in whichthe first film material 10A is folded such that a plurality of firstflat surface sections 11 and a plurality of pairs of side surfacesections 13 and 14 are formed in parallel in the longitudinal directionthereof.

Next, as shown in FIG. 8, parts between adjacent side surface sections13 and 14 of the first film material 10A are heat sealed to the secondfilm material 10B in the longitudinal direction. Furthermore, the partfrom the side surface section 13 positioned near one side edge of thefirst film material 10A to the side edge is heat sealed to the secondfilm material 10B in the longitudinal direction. Moreover, the part fromthe side surface section 14 positioned near the other side edge of thefirst film material 10A to the side edge is heat sealed to the secondfilm material 10B in the longitudinal direction. As a result, aplurality of heat seal sections 15A which becomes the side edge sealsections 15 is formed. Furthermore, the heat seal sections 15A of thefirst film material 10A and the second film material 10B are cut alongthe straight lines X of FIG. 8, that is, in the longitudinal directionat the central parts in the width direction of the heat seal sections15A. As a result, as shown in FIG. 9, a plurality of cylindrical filmmaterials is cut out, each cylindrical film material including flatsurface sections 11 and 12 and side surface sections 13 and 14 with twoside edge seal sections 15 formed.

Step (α2):

In the cylindrical film material obtained in step (α1), parts of theinner surfaces of the flat surface sections 11 and 12 and the sidesurface sections 13 and 14, which become the lower seal sections 17, areheat sealed along the straight lines Y of FIG. 9 which extend in thewidth direction, that is, at regular intervals in the longitudinaldirection of the first film material 10A and the second film material10B. Afterwards, the first film material 10A and the second filmmaterial 10B are cut along the straight lines Y, that is, at regularintervals in the longitudinal direction of the first film material 10Aand the second film material 10B, and are separated into a plurality inthe longitudinal direction, thereby obtaining bag-shaped film materialsin which the lower seal sections 17 are formed at the bottom parts ofthe flat surface sections 11 and 12 and the side surface sections 13 and14. After this cutting operation, the lower seal section 17 is formed atthe bottom part of the bag-shaped film material, and the top partthereof is open.

Next, at the top part of the flat surface sections 11 and 12 and theside surface sections 13 and 14 of each of the bag-shaped film materialsseparated into a plurality, using heat sealing, the opposing innersurfaces of the flat surface sections 11 and 12 are sealed, the contactsurfaces of the flat surface sections 11 and 12 and the side surfacesections 13 and 14 are sealed, and the spout 20 is attached thereto.Furthermore, the contact surfaces of the side surface section 13 aresealed and the contact surfaces of the side surface section 14 aresealed, and as a result, the upper seal section 16 is formed.

For a method of sealing the contact surfaces of the side surface section13 and the contact surfaces of the side surface section 14 at the upperseal section 16, the following method can be given as an example.

As shown in FIG. 10, two punch holes 13 b are formed in the vicinitiesof the side edges of the side surface section 13 so as to oppose eachother. Similarly, two punch holes 14 b are formed in the vicinities ofthe side edges of the side surface section 14 so as to oppose eachother. As shown in FIGS. 5 and 6, the inner surface 11 a of the flatsurface section 11 and the inner surface 12 a of the flat surfacesection 12 which oppose each other are pressed together and heat sealedinside the formed punch holes 13 b, thereby forming a seal section 18.Similarly, the inner surface 11 a of the flat surface section 11 and theinner surface 12 a of the flat surface section 12 which oppose eachother are pressed together and heat sealed inside the formed punch holes14 b, thereby forming another seal section 18. In this manner, thecontact surfaces of the side surface section 13 are sealed and thecontact surfaces of the side surface section 14 are sealed.

Moreover, the method of sealing the contact surfaces of the side surfacesection 13 and the contact surfaces of the side surface section 14 atthe upper seal section 16 is not limited to the above-described method.The contact surfaces of the side surface section 13 or the contactsurfaces of the side surface section 14 may be glued and fastened using;an adhesive, a film having heat sealing characteristics, or adouble-sided adhesive tape.

Using the above steps, the spout-attached gusset bag 1 can be obtained.

In the method of manufacturing a gusset bag and the method ofmanufacturing a spout-attached gusset bag of the present invention, itis preferable to use the above-described method in terms of ease ofmanufacturing. However, the present invention is not limited to theabove-described method.

In step (α1), in order to cut out a plurality of cylindrical filmmaterials including flat surface sections 11 and 12 and side surfacesections 13 and 14 with two side edge seal sections 15 formed, cuttingis performed after heat sealing in the longitudinal direction. However,welding and cutting may be performed at the same time by performing weldand cut sealing (a sealing method in which the material is welded byheat, and at the same time the welded part is cut) in the longitudinaldirection.

Furthermore, in step (α2), among the operation of forming the lower sealsection 17, the operation of cutting the cylindrical film material inthe width direction and separating it into a plurality in thelongitudinal direction, and the operation of attaching the spout 20 andforming the upper seal section 16, any operation may be performed first,or these operations may be performed at the same time. For example,after cutting the cylindrical film material in the width direction andseparating it into a plurality in the longitudinal direction, the bottompart of each of the separated cylindrical film materials may be sealed,and finally the top part to which the spout is attached may be sealed.

In the gusset bag and the spout-attached gusset bag of the presentinvention as described above, since the pair of flat surface sectionsand the pair of side surface sections of the gusset bag are formed oftwo film materials of the first film material and the second filmmaterial, the number of side edge seal sections formed is two, which isa small number, so that it is possible to reduce the pain that a userfeels when he or she squeezes it by hand. In particular, in the casewhere the first film material forms one flat surface section and a pairof side surface sections, no side edge seal section is formed on eachside edge of the flat surface section formed of this first filmmaterial, so that the part that touches the palm is smooth. As a result,even when the contents are pushed out by squeezing the gusset bag byhand, the pain that the user feels can be further reduced.

The gusset bag and the spout-attached gusset bag of the presentinvention are not limited to the gusset bag 10 and the spout-attachedgusset bag 1 described above. For example, the gusset bag and thespout-attached gusset bag of the present invention may include a notchor a cutoff line formed for opening the bag.

Furthermore, a gusset bag of the present invention may be a gusset bag10C as shown in FIG. 11. In the gusset bag 10C, a first film materialforms a flat surface section 11 (first flat surface section) and a sidesurface section 14 (first side surface section), and a second filmmaterial forms a flat surface section 12 (second flat surface section)and a side surface section 13 (second side surface section). That is,two side edge seal sections 15 may be formed at diagonally oppositepositions in the widthwise cross-section of the gusset bag 10C.

INDUSTRIAL APPLICABILITY

The present invention can be widely used for a gusset bag and aspout-attached gusset bag that store contents, and for methods ofmanufacturing them

DESCRIPTION OF REFERENCE SIGNS

-   1 Spout-attached gusset bag-   10, 10C Gusset bag-   10A First film material-   10B Second film material-   11, 12 Flat surface section-   13, 14 Side surface section-   15 Side edge seal section-   20 Spout

1. A gusset bag comprising: an opposing pair of flat surface sections;and an opposing pair of side surface sections folded inward, wherein thepair of flat surface sections and the pair of side surface sectionsinclude a first film material that forms a first flat surface sectionand at least a first side surface section, and a second film materialthat forms the other section thereof, and a side edge seal section isformed in which a side edge section of the first film material and aside edge section of the second film material are sealed.
 2. The gussetbag according to claim 1, wherein the first film material forms thefirst flat surface section and the pair of side surface sections, andthe second film material forms a second flat surface section.
 3. Aspout-attached gusset bag comprising a spout attached to the gusset bagaccording to claim
 1. 4. A spout-attached gusset bag comprising a spoutattached to the gusset bag according to claim
 2. 5. A method ofmanufacturing a gusset bag, used to continuously manufacture the gussetbag according to claim 2, the method comprising: (α1) a step ofconveying a long first film material used to form a first flat surfacesection and a pair of side surface sections, together with a long secondfilm material used to form a second flat surface section, in a state inwhich the first film material is folded such that a plurality of firstflat surface sections and a plurality of pairs of side surface sectionsare formed in parallel in a longitudinal direction thereof, and weldinga part between adjacent side surface sections of the first film materialto the second film material in the longitudinal direction and cuttingthem, welding each part from side surface sections positioned near bothside edges of the first film material to the side edges, to the secondfilm material in the longitudinal direction and cutting them, andobtaining a plurality of cylindrical film materials, each cylindricalfilm material including flat surface sections and side surface sectionswith two side edge seal sections formed; and (α2) a step of welding andcutting the cylindrical film material in a width direction thereof, andseparating the cylindrical film material into a plurality in thelongitudinal direction.
 6. A method of manufacturing a spout-attachedgusset bag that uses the method of manufacturing a gusset bag accordingto claim 5, comprising attaching a spout to each top part of cylindricalfilm materials separated in the longitudinal direction when sealing thetop part.